The invention relates to an axis height adjustable gear box supporting structure which is characterized in that for a unit integrating a gear box and a multistage turbomachine, a position neighboring a split plane of the gear box is supported by a bracket; a sliding pin structure is arranged on the contact surface of the supported position; the bottom surface of a lower box body of the gear box is fit with a bottom plate of the bracket by a guide stand plate; and heat exchange pipelines and temperature sensors are arranged on the bracket. With the adoption of the axis height adjustable gear box supporting structure, the offset of the axis of each gear shaft in an operating process can be controlled conveniently; the heights of the axes are hardly changed with the change of the temperature of a box body; the influence of thermal expansion on the unit is reduced; the operating stability and energy conversion efficiency of the unit are improved; and the axis height adjustable gear box supporting structure is applicable to various gear box type turbomachine units.